Role of the prefrontal cortex and executive control in addiction

The prefrontal cortex is the part of the brain that is the cerebral cortex, which covers the front part frontal lobe. PFC’s most typical psychological term for its functions is executive function. The prefrontal cortex has been associated with a person’s personality by more than one scientist. It is associated with decision making, planning complex cognitive behavior, expressing ones personality as well as controlling and moderating social behaviors. Decision making is a process that is carried out in the brain through the interaction of the prefrontal cortex and the subcortical regions involved in reward and motivation. As a result, it is common that failure in self-regulatory behavior, common in addicted subjects, could be dependent upon the alteration of the interactions between the prefrontal cortex and the subcortical regions.

The PFC has plays a great role in regulating and governing behavior. This function is achieved through a complex interaction of different areas within the prefrontal cortex together with the subcortical areas integrating cognitive and executive functions to produce the “optimal choice”. The result of this interaction can also result in dangerous decisions some of which are observed in drug addicts. The PFC functional abnormalities are very much attributed to the continued use of drugs or traumatic experiences. PFC plays a role in the onset and in the progression of psychiatric disorders associated with very poor decision making such as schizophrenia, attention deficit or the hyperactivity disorder, and depression all of which are very likely to be suffered by drug addicts after a prolonged period of drug and substance abuse.

Dopamine is a neurotransmitter that helps control the brains reward and pleasure areas as well as regulating movement and emotional responses. Dopamine enables us to not only see the reward but to also take actions to move towards them. Addictive drugs such as cocaine, marijuana and nicotine cause an excess of dopamine in the brain. According to scientific theories, dopamine is released in the brain when something very important happens, whether that is an expected reward or an accident. Since it is involved in learning, memory and motivation, the chemical dopamine helps us to store the important information we need to survive as well as to remember it in the future. Drugs however hijack that process sending five to ten times more dopamine surging through the nucleus accumbens and forcing the brains motivational and attention mechanisms to focus purely on the drug. The drug therefore becomes the most important thing in the world which leads to addiction.

Improved performance in cognitive tasks requiring working memory and inhibition have been observed in people that carry variations in the catechol-O-methyltransferase (COMT) gene which degrade the catecholamine neurotransmitters dopamine, epinephrine, and norepinephrine. As a result, when the role of COMT is altered, there could be increased likelihood of making the drug addiction even stronger. Addiction is therefore as a result of a number of factors and the PFC circuitry contributes to the expression of several behaviors that are associated with it. A large number of addicted people do not seek treatment, mostly because they do not even recognize their condition as a disease that requires a medical attention. This condition is probably brought about by viewing the abused substance as an essential ingredient of their life regardless of the consequences of its use.

Imbalance between two separate but interacting neural systems can lead to addiction. These neural systems could be an immediate one that generates decision making, based on the impulsivity-related amygdala system for transmitting pain or pleasure of the immediate prospects and a reflective one, whose basis are for the signaling pain or pleasure of future prospects. The level of controlling behavior is challenged by the ability of cues associated with strengthening activities such as drug abuse, food or sex. Self-control efforts however involve increased activity in the regions of the PFC regulating emotions and cognition and reduced activity in the regions that are associated with reward processing and craving. PFC could be associated with long term outcomes whereas sub-cortical activity is associated with more immediate outcomes.

The PFC is also responsible for the decision to quit taking a certain drug after a period of addiction. Abstinence is a multiple component condition in which the lack of drug effects is highly associated with the inner struggle between the desire of the reward brought about by intake of the drug and the assessment of the consequences of that behavior in terms of money, social life and environmental involvement for example smoking marijuana. This will very fast lead to appearance of withdrawal syndrome that is characterized by depressed mood, irritability, mild cognitive deficits accompanied by other peripheral psychological symptoms as the PFC tries to adjust. Some addicts who struggle to go through the abstinence of a certain drug at times relapse to their old habits. This relapse can be categorized into three major types which are; drug induced relapse, reinstatement of self-administration behavior upon exposition to drug related cues and stress induced relapse. This is a major setback in the recovery of the addicts.

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Research has shown that addicts of strong drugs such as marijuana or cocaine have more problems in their daily lives both physically as well as emotionally. Their health is also very much at risk as this drugs alter the working mechanism of the brain and especially the prefrontal cortex. They report lower life satisfaction, poorer mental and physical health, more relationship problems, and they also have less academic and career success compared to those who do not abuse drugs. Decision making becomes a problem for them and they tend to choose the easy way out which to them is the choice to keep using the drugs. Eventually, they could lose their mind all together as the brain function mechanism gets more and more accustomed to the drug effects.